The present invention relates to magnetic tape cassettes, and more particularly to a compact cassette of the same or smaller size as the "Phillips" type compact cassette.
Recently, cassette tape recorders have been reduced both in size and in weight, and accordingly magnetic tape cassettes have also been miniaturized. Therefore, there has been a strong demand for the provision of small magnetic tape cassettes which are suitable for high-quality high-density long play recording and reproducing operations. Magnetic tape cassettes satisfying this requirement are operated according to a digital system such as a PCM (pulse code modulation) system in which recording and reproducing operations are carried out with input signals converted into pulse signals. In this system, the recording frequency band must be about five times as wide as that of a conventional audio tape. Therefore, video tape cassettes of larger size than compact audio cassettes are extensively employed with this recording system.
Video tape cassettes are typically operated in a rotary head system. The video tape cassettes have a guard panel which is upwardly swingable and which closes the opening which is formed in the front part thereof. The guard panel prevents the entrance of dust and protects the magnetic tape from damage.
The invention relates to a very small magnetic tape cassette which, similarly to video tape cassettes, employs a relatively wide frequency band recording and reproducing system. The cassette is usable with audio devices, and is equal to or smaller than the conventional compact audio cassette in size. Accordingly, the magnetic tape cassette is intricate in construction when compared with a conventional compact audio cassette, and therefore it is rather difficult to assemble. Furthermore, it is expected that the magnetic tape cassette may be frequently used outdoors. Accordingly, it is necessary for the magnetic tape cassette to have a structure which provides a dust-proofing effect. In addition, it is essential for the magnetic tape cassette to be designed so as to positively prevent jamming which occurs when the cassette is vibrated and the tape slackened while being carried.